Both Germany and Britain have troops in Afghanistan as part of NATO's International Security Assistance Force (ISAF), which comprises around 30,000 troops.
NATO, whose Secretary-General Jaap de Hoop Scheffer has characterized the Afghan mission as among "the most challenging tasks NATO has ever taken on" and one that is "a critical to international security," is preparing for a major summit in Riga on November 28-29.
Merkel said Afghanistan needs more than just a military solution to solve its problems.
"It is more than understandable that the civilian community asks questions, how it is and how it will be, and I think -- and we agree upon that -- that a military solution is one thing, and very necessary, but it is not the only one to succeed," Merkel said in London.
Blair and Merkel reportedly focused in their discussion on rebuilding Afghanistan's institutions and fighting the drug trade.
The two also discussed affairs in the Middle East. Merkel reportedly promised to support Britain's initiative to give Syria a chance to play a more constructive role in the Middle East, particularly with regard to Lebanon.